It's a shame Rachel, but you did the right thing. Is there anywhere you can get off-road at that time of the morning? It's often less slippy, and you get more of a workout for less speed, if you see what I mean. Not too many floodlit tracks though!
Another option is shoes - some road shoes are OK in slippy conditions, others are just awful. Studded trail shoes (I've use Mizuno Wave Harriers, others are available) are better on ice as well as being better off road than road shoes (well duh!). Not a cheap option though, but if ever you needed an excuse to try some new shoes then this is it.
Welcome Ricky. You seem to have a similar schedule to Rachel. That's an impressive weight reduction by any standards, are you now at racing weight or is there more to come?
I've never really looked at getting my own treadmill, I went through a streak when it seemed every hotel treadmill I got on conked out on me so I didn't fancy spending my own money on something as unreliable. I have a turbo trainer for my bike that serves when I can't get outdoors. Have a word on the Gear section, treadmills come up quite often and I'm sure someone can suggest something that fits the bill.